Telephone system



ct. 10, 1933. HOFF TELEPHONE SYSTEM Filed March 7, 1932 MSR .RS mm L m .SQ a@ @s u V Hans T T-EF1;

Patented oet.10,1933 I Y f l i 1,929,587-

omreiic srArEs Farrar orties TELEPHONE SYSTEM Hans Hopf, Berlin-'Charlottenburg Germany, as-` sign'or to Siemens & Halske, Aktiengesellschaft, Siemei'sstadt; near Berlin, Germany Application March 7, 1932, Serial No. 597,197, v and in Germany May 22, 193i y Y 7 claims. (o1. 179-27) This invention relates to a circuit arrangement 1t and 2t and switches through said vspeaking for automatic telephone systems in which conleads to the rst group selector by closing its connections of high and low value are set up over` the tacts 715 and St. In addition, relay T short ciry same connecting devices. l cuits its Winding I over contact Litand the switch 5 There are known arrangements for such syswiper d, and in this manner guards the rst group 60 tems by which an existing connection of low selector against further seizure. value, such as for example, a local call, may be The two feeding bridge relays A and B in the l cut offin favor of a connection of high Value, rst group selector are now energized overthe such as a toll call. s`\vitched=through subscribers line loop. Relay 1o It is frequently required, however, that existing B removes the short circuit for relay C by open# 65 connections set up by privileged subscribers ing the contact 14h, thus energizing relay C also shouldnot be cut olf even if they are engaged inl Which is preparatorily placed in a locking circuit i a connection of low value. A simple and satisover contact 12e independent of the olf-normal factory solution of theproblern isvprov'id'ed by the Contact 111e. By closing contact 41C itswitc'hes 15` invention, this being that the connecting devices through the b-lead, whereas, by opening contact 70 by which. connections of low value are caused to 39C the metering relay Zr is cut off from this lead; be'cut off in favor of connections of high value, The subscriber Tn now dials the impulse series are associated with switching devices which on required for the setting of the first groupV selector; the seizure of va denite group of junction lines The returning dial then causes the impulse conaccesslible over said connecting devices for con tact nsi to be intermittently opened and closed 75 nections of low value, prevent 'such connections whereby in consequence, relay A in therst group from being cut off in favor of connections of high selector is intermittently energized and deenervalue. rgized. Contact 13a, therefore, intermittently "The accompanying drawing shows a embodyshort circuitswinding I of relay B, thus causing ment ofthe invention. Fig i shows the switches it to remain energized for the duration .of the 80 40 1t, winding I of relay R, battery, earth. Relay R following circuit for the vertical magnet Hg of the"l and circuits involved in a complete lconnection Whole impulse Series. v between two subscribers; while Figs.` .2 and 3 The subscriber T111 may belong to a group of show modified forms'of thev metering circuits subscribers whose local calls are not to be out shown in Fig. 1. off by the toll operatorevenin the case of a toll According to this embodiment a connection of call. The subscriber Tril is accessible over ,af

low value, in this instance a local connection, is definite group of final. sectors connected to a eet up' between the subseribersTn and Tm over dennite group 0f 'Contacts (level) 0f the rst g, pre-Selector VW, a first group selector IGW andY `group selector. In the embodiment this level is a connector or final selector LWl. A local call is the fifth level. In order to reach the subscriber initiated by, for example, the subscriber Tn lift# T'nl, the'subsrber `Tf1 must 'rst dial the digit ing his reeeiventhussetting'up the followingcir- 5. The impulse contact mi is then opened and cuit for relay R in theV preselector VW: earth, closed ve times in succession and relay A, as winding II of relayV R, contact 2t, closed sub- .mentionedabova is accordingly energized and scribers line loop, impulse contactvns, contact de-energized an equal number of times. The 5 is energized and closes the following circuit for first group selector is completed each time relay the rotary magnet of the preselector VW:r earth, A releases: earth, contacts 24e, 25a, winding II interrupterA RU,"winding of rotary rnagnet Dv', of relay V, 'contact 29d, Vrotary off normal concontacts Gt, 3T, battery,- earth. The preselector tact 28m, winding of vertical magnet Hg batterycommences to hunt for a line leading to an idle earth. Relay V is energized in this circuit and 100 first group selector and continues hunting until due' tothe short circuiting of its vwinding I func'- such a group selector has been encountered which tions as a slow acting relay and. consequentlyin this case may be the shown group selector IGW. remainsY energized during the impulse series. ItI When this has been found, relay T associated releases 'at the end of this impulse series, when with the preselector VW is energized in the'fol;Y the following circuit for the rotary magnety of 105 lowing Circuitr'aith,' battery, Contact 5r', w'indthe rst group 'seleetoris completed: earth, conines I and II of relay T.- c-Wipe of the presele'cmets 22p, 21e, 3g-normal Contact 207e, winding tor VW, resistance Wil, contact 14D', ff-norma). Dg 0f theprst' groupselector, battery, n earth.r COII'GC 117C, afhf REMY' T dSIIeC'S Ielly The group selector advances one 'step'.y Contact 110 5 from the speaking leads by opening its contact 30d is closed on each energiz'ation ofthe rotary Yresistance winding I in this locking circuit. closing of contact 5301 prepares the testl circuit magnet Dg so that relay V is energized over: earth, contact 30d, winding I of relay V, winding ci the vertical magnet Hg, battery, earth. The'vertical magnet is not energized in this circuit. Relay 'V opens the circuit for the rotary magnet by means of contact 2112. The rotary magnet Dg and relay V interact in this manner and cause the switch wipers of the first group selector to advance stepby-step. As soon as the wipers of the first group selector have reached the rst contact in the iiith level, the switch wiper e closes the contact rk, allocated to the fifth level, and this Contact is only reopened when the wiper leaves the last contact in this level.

As soon as the iirst group selector has round a line leading to an idle iinal selector, for example, the shown final selector LWl, the following test circuit is completed: earth, contacts 40o, 38a, windings I and II of relay P, c-wiper of the first group selector, ofi-normal contact 51761, winding Il of relay C1, battery, earth. Relays P and Cl are energized in this circuit. Relay P in the i-lrst group selector switches through the two speaking leads when it closes its contacts 35p and Its contact 34p short circuits its high resistance winding I and thereby guards the seized line against further seizures. The circuit for the rotary magnet is cut oirwhen contact 22p is opened. Contact 18p applies earth to the c-lead over the resistance W and thus prepares alocling circuit for the test relay oi the preceding preselector VW, which is caused to function at the metering.

Relay C1 in the ilnal` selector LWl is placed in its own locking circuit over contact 5G01 and, therefore, at the Sametime, connects up the high The to the subscriber to be called due to contact 5401 closing the circuit for a locking winding of the test relay Pl. The additional impulse series for the setting of the nal selector LWl are transmitted to relay A in the first group selector by the impulse contact 'nei intermittently opening and closing the line loop, and said group selector transmits them further by applying earth over contacts 40e, 37a, 35p, cwiper of the'rst group selector, resistance Wi?, winding of relay Al, battery, earth in the iinal selector LWl. to the vertical and rotary magnet of the inai selector. These circuits are of no importance for the invention and, therefore, have been omitted.

, high resistance winding II of relay P1 and so guards the seized subscribers line in known manner. The following locking circuit for relay P1 is closed over winding III: earth, contact Elcl, winding III of relay P1, contact 59331, bat

l tery, earth. Ringing current is now automatical ly appli'edfrom the final selector Ll/vl to the subscriber T721. When he lifts his receiver, the two feeding bridge relays Al and Y1 in the seru lector LWI are energized over the closed sul scribers line loop. Metering potential is applied to the b-lead over contacts 61111 and 60g/1.

It may now occur that either the subscriber Relay Al transmits the impulses` Vto the subscriber Tn again has no effect.

Tnl or Tn is wanted on a toll call while already engaged in the above described local call.

v The case of the subscriber 'Inl being wanted for a toll call will rst be considered. The call from the distant subscriber is ultimately received at the toll operators position FP. The operator at this'position FP connects herself to the required subscriber by inserting the plug St in the 4jack KL. A toll group selector FGW is then seized and set by dialling to an idle final selector LWZ, multiple connected to the 'nal selector Ll. Relay C2 is then energized over: earth, c-wiper of the toll group selector FGW, windings or relay C2, battery, earth in the final selector LwZ. The final selector LWZ is now set by the toll operator dialling the required subscriber Tcl. The circuits associated with this operation are lof no importance to the invention and therefore have not been shown. The subscribed Tril being engaged in a local call, however, the test relay P2 associated with the final selector LIX/V2 cannot carry out the testing operation. The toll operator endeavors to cut oi the existing local call after having informedthe subscriber Tal to this eiiect, and with this Yobject in view depresses the cute-oit key TT, Vat the operators position This energizes relay A2 in the nal selector LW2 over: earth, key TT, plug St, jack KL, a-Vwiper or the toll group selector FGW, winding of relay A2, battery, earth. At the same time relay Y2 in the iinal selector lLili/2 is energizedlover: earth,

battery, key TT, plug St, jack KL, L7-wiper oithe toll group selector FGW, contact 63a2, re-

cially favored subscribers are accessible, for eX-- ample, the ,nal selector, LWZ, applying earth direct to thee-lead over a final selector seized from the toll operators position would'shortcircuit the test relayV P2, and cause the release of a subscribers line seized over this final selector. The short-circuitnrT of winding I of relay PI in the ilnal selector'LWl, however, has no erect as the test relay P1 is disposed in a local locking circuit in the iinal selector LWI as described above.Y The disconnection of a toll rec earth applied to the b and c leads by the tollfA i operator after the setting of a final selector LW2 The windings I and Il of relay B connected to the 'b-lead inthe first group selector, however, are be released,

incassi When the called subscriber replaces his re ceiverat the end of the call, lrelay A1 inthe iinal selector LWl is rapidly released. This closes the followingv locking circuit for relay Y1:

ing ci relay Y1, resistance WiS, conearth, win ---g tacts 55051, 6cyl, 61291, battery, earth. v When the calling subscriber also hangs yiin-the eedingbridge relay A releases iirst due to the .freaking of the subscribers line; loop.. Relay Rho-Wever, is still maintained energized.r over itsy winding 111. Due to the release. of relay A, the following circuit for relay V is completed: earth, contacts 24o, 25a, windings Hand?.l 'of relay V, winding of the Vertical magnet EQ, battery, earth. Thel vertical magnet Hg is not encrgizedin this circuit. Relay V, however, is energized and short-circuits winding 111 of relay B by closing its contact i711. RelayY also is now released and by closing its Contact 14h short-circuits relay C. Relay C releases and cuts ofi the above-mentioned circuit for relay V by opening its contact 24o. lease of the first group selector, however, is still prevented byrelay P `being maintained energized over: earth, winding 11i, contacts 43o, 352.9,y 1.-wiper of the irst group selector, resistance Wi?. winding of relay Al in the final selector LWL battery, earth, until the metering is completed. Relay Al in the final selector LW 1 is not energized in this circuit. `The following circuit for relay Zr in the first group selector is set by the release of relay C: Aearth contact 39C, widing of relay Zr, Contact p, @wiper ci the hrst group selector', contacts 60g/l, Glpi, battery, earth. If the calls completed over the first group selector are to be metered, relay Zr closes its contacts 15er and 16er, thereby applying earth direct to the c-lead in the manner illustrated in Fig. 8.

This energizes in known manner the I.metering relay Z associated with the preselector VW belonging to the calling subscriber Tn.

Y. If the calls for the privileged subscribers con-Y nected to level 5 of lthe rst group selector also are to be metered, the metering circuit (Fig. 1) after closing contacts 15er and 16er, extends over: earth, c-wiper ofthe first group selector, level contact 17c5, contact 15er, c-lead to the metering relay Z of the preselector VW.

1f the calls completed over the remaining lev-A els oi the rst group selector are to be metered, but not those extending over level 5 of said group selector, there is no connection between the c-lead and the level contact fk5, but the metering circuit (Fig. 2) for the remainingconnections extend over: earth, switch wiper r, contact xk of the iirst group selector, `contact 1521 to the metering relay Z oi the group selector VW. The switch wiper X and contact mit represent the switch wipers and level contacts associated with the other levels of the iirst group selector, and correspond to the switch wiper e and the level contacts fk5 for level 5.

The winding III of relay l? is shortcircuited over contact 44er when relay Zr is energized. Relay P releases with slow action and opens the test circuit extendingV to the preselector VW by Y, opening its yContact 18p. Relay T in the preselector VW also releases and closes a circuit for the rotary magnet Dc of the preselector over the d-wiper and contact' Gt. The preselector VW then advances step by step until it reaches its original position in which the ril-wiper cuts F off the circuit for the rotary magnet.

cut

'or relay'Pl the-release of the linal selector LWl is initiated in known manner and in addition the locking circuit vfor the `feeding bridge relay Y1 is cut off bythe opening of contact 61211. The*followingl circuit for the rotary magnet D9 the first group selector is closed by the release of relay 1: earth, contacts 22:9, 2li), off-norn malcontact 207s, winding 'of the rotary magnet Bg, battery, earth Contact 30d is closed as soon as rotary magnet is energized and'causes relay V to be energized'cver its winding I. Contact 2112 breaks the circuit for the rotary magnet. -f The rctary'inagnet releases, causing contact 30d to open. Relay V is released and recloses thecircuit of the rotarymagnet Dg. The interaction'between the rotary magnet Dc' and relay V in the manner described above causes the rotaryrnagnet Dg to operate until the switch wipers have been restored to normal, the rolifnormal'contact 20k has been opened and the cir'- cuit for the rotary magnet finally` cutv off.

f n the present embodiment the switching devices which are provided to prevent local calls from being cut oi in favor of toll calls are associated kwith a first group selector and a final 105 selector functioning as connecting devices in with either all the connected lines or only a portion' thereof' and furthermore,` an embodiment in which local calls are cut orf under denite working conditions, only,'nan1ely, whether the subscriber to be cut oi is the calling or the called party.

What is claimed is:

l. `In a telephone system, a called line, a calling line, a toll operators position, means involving a connector to connect said calling and called lines, a toll group selector and a second connector to extend a connection to said called line, means at said operators position'to shunt the holding relay of said .rst connector in an attempt to revlease the same, and .means including a third winding on said holding relay to prevent said toll 13() operator from releasing said iirst connector.

2.v In a telephone system, a calling line, a called line, a toll operators position, means including a connector to connect said calling n and called lines, a holding relay in said connector, a multiple ci said called line terminating in a second oonv neet-or, means including a toll group selector and said second connector to extend a connection to said called line, means at said toll operators posi'- tion to place ground on said multiple shunting said holding relay to release said iirst connector, a third Winding on said holding relay, and means to hold said thirdy .winding energized to prevent said operator from releasing said connector;

3. In a telephone system, a calling line, a called 141.5 line, a toll operators position, means including a group selector and a connector to connect said calling and called lines, a toll group selector and a connector to connect the operator at said posiposition to shunt the control relay of said group selector, a third winding on said control relay, and means including said third winding to prevent said toll operator from releasing said group selector.

4. In a telephone system, a group selector, a calling line having access to said selector, a control relay in said group selector, a plurality of bank levels on said group selector, means to cause said group selector to be raised to'any bank level, a toll operators position, a toll group selector and a connector to connect theoperator at said position to said calling line, means at said toll operators position to shunt said control relay to release said group selector, a third winding on said control relay, and means effective on certain levels of said group selector to hold said third winding energized to prevent the release of said group selector.

5. In a telephone system, a calling line, a plurality o called lines, a group selector, a control relay in said group selector, means including said group selector for selecting any one of said called lines, a toll operators position, a toll group selector and a connector to connect the operator at said position to said calling line, means at said toll operators position to shunt said control relay in an attempt to release said selector, a third winding on said control relay, and means effective on the selection of certain called lines to hold said vthird winding energized to prevent the release of said group selector.

6. In a telephone system, a plurality of groups of subscribers lines, a group of preferred subscriberslines; a toll switchboard, automatic switching mechanism including group selectors and connectors for connecting any subscribers line with any other subscribers line and for extending a connection from said switchboard to any subscribers'line, means in the connectors accessible from said switchboard effective to alter the circuit condition ofthe line multiple of a subscribers line which is called from one or said connectors and found busy, for the purpose of breaking down the connection to such busy line, and means only in the connectors which nave access tovsaid preferred lines for preventing such alteration Vfrom being effective.

'7. A telephone system asset forth in clairn 6 in which each of the group selectors is provided with an arrangement which is effective to prevent its release from one of the connectors used the toll operator when such connector is set on a Vcalling line, said arrangement being effective only if the associated group selector is set on a connector which has access to said preferred lines.

HANS HOFF.

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